The contractor will serve as the Data Coordinating Center (DCC) for a multisite, longitudinal MRI study of normal pediatric brain development. A sample of normal infants, children and adolescents representative of the population of the United States will be studied with brain MRI scans and clinical/behavioral measures at several Pediatric Study Centers (PSCs) across the U.S. The primary imaging modality will be structural MRI, supplemented where feasible with magnetic resonance spectroscopy and diffusion tensor imaging (DTI). The study is organized around two "objectives": Objective 1 enrolls children ages 4 1/2 to 18 years old and follows them longitudinally at 2 year intervals for a total of three timepoints. Thus, the oldest subjects will be age 24 upon completion of the study. Objective 2 enrolls newborns, infants and preschoolers (ages 7 days to 4 years, 5 months) and follows them longitudinally at intervals ranging from 3 months at the youngest ages through 1 year at the oldest end of the age range for three or more timepoints, depending upon the willingness of the families to return to the center. The DCC is responsible for coordinating the imaging aspects of the study, as well as for coordinating the data collection, data transfer and entry and image analysis and all aspects of the database to be produced as a resource for the scientific community. The DCC will work with the Clinical Coordinating Center (CCC), which has responsibility for the clinical/behavioral measures, sampling plan (in coordination with the DCC's statistician), subject selection criteria, staff training, certification and quality controls for the collection of the clinical/behavioral data. A Spectroscopy Processing Center and a Diffusion Processing Center will process the spectroscopy and DTI data, respectively, and provide the processed data to the DCC for integration into the project database.